Thermodynamics of uptake of cadmium by Chlorella marina

Microorganisms in inorganic chemical analysis

There are innumerable strains of microbes (bacteria, yeast and fungi) that degrade or transform chemicals and compounds into simpler, safer or less toxic substances. These bioprocesses have been used for centuries in the treatment of municipal wastes, in wine, cheese and bread making, and in bioleaching and metal recovery processes. Recent literature shows that microorganisms can be also used as effective sorbents for solid phase extraction procedures. This review reveals that fundamental nonanalytical studies on the parameters and conditions of biosorption processes and on metal-biomass interactions often result in efficient analytical procedures and biotechnological applications. Some selected examples illustrate the latest developments in the biosorption of metals by microbial biomass, which have opened the door to the application of microorganisms to analyte preconcentration, matrix separation and speciation analysis.

Kinetics of uptake of cadmium by Chlorella marina in different media

The kinetics of cadmium binding to living Chlorella marina cells during a short time (a few minutes) has been studied in seawater conditions, being also considered separately the influence of calcium and chloride. Cadmium complexes with surface groups of C. marina cells are labile in terms of differential pulse anodic stripping voltammetry in media (0.01-0.7) M NaNO3 since the complexation reaction is kinetically fast. However, in media 0.7 M NaCl, 0.7 M NaCl + 10(-2) M Ca2- and in synthetic seawater diluted 1:4 or not, the complexes are inert, since kinetics is determined by the rate of exchange with alkaline-earth metals and/or the chloride anion.